Problem in ver. 0.7, should I upgrade?

Hi,

I'm having a very strange problem with version 0.7 on Elgg version 1.5.

Suddenly it moved all events 1 day forward, so instead of "Tuesday, January 19, 2010" the date changed to "Monday, January 18, 2010" - this happended to all my events!

I haven't changed anything since before newyear, so is this possible?

Anyway, I'm considering to upgrade to version 0.81. Is there anything that I should take into consideration before upgrading?

Regards